Logo link to homepage

Report on Kilauea (United States) — October 1985


Kilauea

Scientific Event Alert Network Bulletin, vol. 10, no. 10 (October 1985)
Managing Editor: Lindsay McClelland.

Kilauea (United States) Episodes 37, 38, and 39 of 1983-85 eruption

Please cite this report as:

Global Volcanism Program, 1985. Report on Kilauea (United States) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 10:10. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198510-332010



Kilauea

United States

19.421°N, 155.287°W; summit elev. 1222 m

All times are local (unless otherwise noted)


"Episode 37 produced a lava volume of 14.7 x 106 m3. During the 26-day repose period that followed episode 37, the summit tiltmeter recorded 13.0 µrad of inflation. Summit subsidence associated with episode 38 began on 20 October at 1900, nearly simultaneously with the onset of low-level, discontinuous activity at the Pu`u `O`o vent. Intermittent dome fountaining produced thin pahoehoe spillovers for the next 8 hours.

EPISODE 38

"Beginning at 0230 on 21 October, a gradual increase in tremor amplitude was recorded by the seismometer near Pu`u `O`o. Continuous lava production began at 0301, signalling the official beginning of episode 38. Fountain heights reached approximately 300 m by 0607. Broad aa flows advanced SE, closely following the path of the episode 37 flows (figure 38) and eventually stagnating 4.2 km from the vent.

Figure (see Caption) Figure 38. Lava flows produced on Kīlauea's E rift zone since January 1983. Episodes 37 (top) and 38 (bottom) are shown separately. Courtesy of HVO.

"Harmonic tremor amplitude began to decrease rapidly at 1118, and the fountain died at 1120. By 1145 the tremor was at a non-eruptive level. Gas-piston activity followed the end of the eruptive episode for about 24 hours, before continuous low-amplitude background tremor resumed. Summit subsidence continued until about 1500 on 21 October, resulting in a net deflation of 13.0 µrad (figure 37). Following the eruption, the familiar pattern of summit reinflation resumed, and by the end of October, the summit tiltmeter had recorded a net gain of 9.5 µrad."

Addendum: On 13 November at 0530, low-level activity at Pu`u `O`o signaled the onset of episode 39. At 1534 continuous lava production began with fountain heights reaching an estimated 260 m, producing lava flows that extended about 6 km E. Vigorous activity lasted nearly 10 hours, stopping at 0124 on 14 November.

Geological Summary. Kilauea overlaps the E flank of the massive Mauna Loa shield volcano in the island of Hawaii. Eruptions are prominent in Polynesian legends; written documentation since 1820 records frequent summit and flank lava flow eruptions interspersed with periods of long-term lava lake activity at Halemaumau crater in the summit caldera until 1924. The 3 x 5 km caldera was formed in several stages about 1,500 years ago and during the 18th century; eruptions have also originated from the lengthy East and Southwest rift zones, which extend to the ocean in both directions. About 90% of the surface of the basaltic shield volcano is formed of lava flows less than about 1,100 years old; 70% of the surface is younger than 600 years. The long-term eruption from the East rift zone between 1983 and 2018 produced lava flows covering more than 100 km2, destroyed hundreds of houses, and added new coastline.

Information Contacts: C. Heliker, G. Ulrich, R. Hanatani, and J. Nakata, HVO.